Magnetic brake-shoe.



E. H. GOGKSHOTT a: AIWJMAL Y.

MAGNETIC BRAKE SHOE. APPLIOA'I'IOH TILED AUG. 27, 1908. RENEWED JUNE 16, 1910. 965,798.

Patented July 26, 1910.

UNI

ED STATES Parana: ormon.

EDGAR HARRY ooonsnorr, or LEEDS, AND ALFRED WALTER MALEY, or WEST BROIVIWIGH, ENGLAND.

MAGNETIC BBAKESHOE;

scares.

Specification of Letters Patent.

Patented July 26, 1910.

Application filed August 27, 1908, Serial No. 450,472. Renewed June 16, 1910. Serial No. 567,315.

To all whom it may concern:

Be it known that we, EDGAR H RRY Goon sHor'r, a subject of the King of Great Britain, residing at 408 Meanwood road, Leeds, in the county of York, England, and Ammo VVALTER MALEY, a subject of the King of Great Britain, residing at Eagle Foundry, Moor street, West Bromwich, in the county of Staiford, England, have invented a new and useful Magnetic Brake- Shoe of which the following is a specification.

This invention relates especially to the form of construction of the electromagnets employed upon trams, trains and the like as brakes. In the most efficient form known to us the electromagnets are provided with two long narrow pole shoes lying side by side over the rail, their greater dimension being of course parallel with the direction of the rail. These brake shoes have the disadvantage that the oscillation of the magnet upon its flexible support often carries one pole of the electromagnet wholly or almost wholly oil the rail, so introducing an air gap into the magnetic circuit, or at the least largely diminishing the available sectional area of the iron. In another form of magnet the poles are arranged along the length of the rail, but with this arrangement the area of iron available for the magnetic flux is obviously limited by the width and sectional area of the rail which of course cannot be increased simply for the purpose of braking. A certain increase in available sectional area has been obtained by the multiplication of poles, some half dozen or so being provided, alternately of opposite sign, along the length of the rail, but this type is in our experience not so eflicient and is costly to construct. According to the present invention a construction is adopted for these electromagnets which secures the advantages of both the constructions above described.

It consists in forming the elect-romagnets, which may be bi-polar or multi-polar, with concentric pole pieces, that is, with the pole piece of one sign surrounding the pole piece of opposite sign.

The invention is illustrated in the accompanying drawings in which Figure 1 is a side elevation of an electroinagnet suitable for this purpose; Fig. 2 is an endelevation of the same, Fig. 3 a plan view looking from underneath; Fig. 4: a cross section on the line AB of Fig. 1; and Figs. 5 and 6 are part sections on the lines A-B of Fig; l and G--D of Fig. 3 indieating the course of the magnetic lines of force.

In the form illustrated the electromagnet is strictly of the bi-polar type, but the one pole piece is divided into a number of sections each of which occupies a space provided in the other pole piece.

In the drawing a is the yoke of suitable form, in the center of which is placed a winding 6 by which the magnet is excited. It is clear that with different forms of yoke the winding may be put in different posi tions, but whether its axis is vertical or horizontal 0'1- inclined, does not affect the presentinvention. To one end of the yoke 64 is bolted the pole piece 0, which adjacent to the yoke is continuous but at the free end which is brought into a vertical position centrally beneath the yoke, is divided into a number of separate poles (Z. The pole piece of opposite sign 6 is secured in the same way to the yoke and also terminates in a vertical portion centrally beneath the yoke. The free end of this pole however, is broader than the pole piece 0 and has formed in it a number of holes of rather greater dimensions than the ends cl of the pole piece 0, one of which ends passes into each of the holes. As illustrated in the drawing the pole ends cl and the holes 7 are made roughly elliptic in section. It is clear that this section may be modified at will and may be made square or circular or rectangular as desired. Naturally the space which must be left between the pole ends d and the side of the holes f governed by considerations of magnetic leakage and so forth, and must be suflicient to insure the passage of a fair proportion of the flux through the rail. If desired, the available space between the ends cl and the sides of the holes f may be filled or partiallyfilled by stays or the like of nonmagnetic material. It is hardly necessary to point out that polepieces of this form combine the possibilities of those previously used. The magnetic flux can both pass along the length of the rail and also across it, (Figs. 5 and 6,) and the diminution of the area of this path through lateral motion of ioo winding adapted to carry current to excite said magnet.

2-. In a track brake electroinagnet, an iron core, a plurality of poles secured to one end of said core, a second set of poles, each surrounding one pole of the first set ofsuch width as to contact with the rail of the track at the sides as well as the ends, said poles being attached to the other end of the core, and a Winding adapted to carry current to excite said magnet.

3. In a track brake electroinagnet, an iron core, a plurality of poles secured to one end of said core, and projecting at right angles thereto, a second set of poles, also projecting at right angles, each surrounding one pole of the first set, and attached to the other end. of the core, and a wlndlng on said core coaXial therewith adapted to carry current to excite said magnet.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

EDGAR HARRY COCKSI-IOTT.

ALFRED WALTER MALEY. Witnesses:

EDWARD NORMAN GAUN'I,

ALBERT McCoLeAN. 

